Mine safety catch



May 29, 1956 H. w. VANDERGRIFF 2,747,690

MINE SAFETY CATCH Filed Dec. 19, 1952 2 Sheets-Sheet l /0 3 30 F g. ...of .ffzv 'y f7 54 ff/ .l 1^ 4 36 fn 4 \/2 24 4 'n ifm l "-U'i 7 g@ 6 A 70 Henry W.- Vandergr/'ff 56 32 B5/84 INVENTOR. F v 5 I il K BY i g- 80/ mm May 29, 1956 H. W. VANDERGRIFF MINE SAFETY CATCH 2 Sheets-Sheet 2 Filed Dec. 19, 1952 Henry Vandergr/f 1 BY aaa/Wawy 5mt),

United States Patent MINE SAFETY CATCH Henry W. Vandergrilf, Atkins, Va.

Application December 19, 1952, Serial No. 326,865

2 Claims. (Cl. 187 81) This invention relates to a mine safety catch and par ticularly to an automatic device for applying the brakes to a mine hoist in the event the lifting cable should be broken or released.

In the operation of mines of various types it is frequently desirable to provide shaft communication between the surface of the ground or between various parts of the mine and for this purpose it is customary to provide substantially vertical shafts with hoist operating in Vertical movement in the shafts and controlled usually by means of cable or other supporting means controlled preferably from the surface or top of the shaft. The cages in such mine shafts are usually of relatively large size so that considerable loads are carried and are frequently operated at relatively high speeds to speed up the mining operations. Usually the mine cages are provided with suitable guide means engaging vertical guide rails in the shafts to prevent undue transverse movement of the cages in the shaft. Frequently various types of safety devices are applied in the cages so if they should be released for free fall some sort of gripping arrangement will connect to the guide rails to slow down or if possible stop the fall of the cage in the shaft. Itis frequently found that the application of a grab means to the guide rail results in destroying the guide rail by tearing it loose from the sides of the shaft resulting in extensive damage and frequently failing to completely stop the car so that it falls to the bottom of the shaft with resultant injury to passengers and material thereon.

The present invention provides brake shoes for automatic engagement with the concrete sides of the mine shaft in the event the cable should break or be released so that the cage would fall freely in the shaft.

The construction according to the present invention provides an articulated brake rod which when extended will make contact with the opposite sides of the mine shaft and which has friction shoes mounted thereon for engagement with the side Walls of the shaft and a con nection between the supporting cable and the articulated rod so that the articulated rod is bent at the articulation to withdraw the shoes from contact with the side walls of the shaft when the bight of the cage is being supported on the cables. This is accomplished by means of a resilient connection between the lifting members connected to the cable and a supporting element or bracket mounted adjacent the top of the cage so that when the weight of the cage is applied onto the cables the resilient element will be compressed so that the articulated arms will be folded to withdraw the shoes and whenever the cable is released the tension of the resilient element will straighten out the articulated arms and produce a braking action. This has a particular advantage in that the braking action is immediately applied in the event of the breaking or release of the cable and there is no necessity of waiting until the cage has acquired a high speed to actuate a braking mechanism.

It is accordingly an object of the invention to provide an improved brake mechanism for a mine cage.

It is a further object of the invention to provide an automatic safety brake for a mine cage.

It is a furtherobject of the invention to provide a safety catch applied immediately upon the release of the cage supporting cable.

Other objects and many of the attendant advantages of the present invention will be apparent from the following detailed description taken in conjunction with the accompanying drawing in which:

Figure 1 is a vertical elevation through a mine shaft and hoist showing the safety brake in released position;

Figure 2 is a fragmentary view similar to Figure 1 showing the brakes in applied position;

Figure 3 is a transverse elevation taken substantially on the plane indicated by the line 3 3 of Figure l;

Figure 4 is a cross-section taken substantially on the plane indicated by the line 4 4 of Figure 1; and

Figure 5 is an enlarged cross-section through the brake shoe taken substantially on the plane indicated by thel line 5 5 of Figure 1. v

ln the exemplary embodiment according to the invention the mine shaft 10 is provided with a cementitious liner i2 and is pro-vided with vertical guide rails 14. The vertical guide rails 14 are usually constructed of planks dovetailed together or spliced together to provide a composite timber of considerable size extending the full length of the shaft. A skip or hoist 16 is provided with a substantial floor 18 together with end members 2t! and 22 and a top 24 which may be of any desired width and frequently is of sucient Width to cover the entire floor structure 18 but herein shown as being of relatively narrow width.

Erackets 26 and 23 are provided on each of the ends 2t? and 22 closely engaging the guide rails 14 so that the cage 16 is prevented from lateral movement or rattlingl about in the shaft. l

The cage 16 is supported by any suitable means such as the cable indicated at 30 connected to a suitable lifting member 32 which is herein shown as having an arcuate top or bight portion 34 and depending side portions or legs 36 and 3S. For simplicity of illustration the members 3d and 36 and 33 are shown as rod but obviously they will be made of any structural configuration necessary to withstand the load and other operating conditions to which they are subjected.

The braking arrangement according to the invention comprises a pair of spaced apart brackets 40 and 42' preferably spaced adjacent both of the outer edges of the floor member 1S and having upwardly extending horizontally spaced stirrups 44 and 46 including suitably supported transverse rollers i and 50, respectively. An articulated brake rod 52 having arms 54 and 56 pivoted together and is joined to the lifting members 36 and 38 by means of bridles 58, the three pieces being joined together by means of a suitabie pin 60. The lifting members 36 and 38 respectively extend upwardly through supporting brackets 62 and 6d. The supporting members 62 and 6d being respectively provided with apertures 6e and 68 through which the members 36 and 38 are slidably extended. The members 36 and 38 likewise extend through suitable apertures in the top 24 for connection to the bridle portion 3d and connection to the cable 30. Compressible members shown as spiral springs 70 and 72 are provided on the members 36 and 38 between the yokes 5S and the respective supporting brackets 62 and 64. The members 70 and 72 are sufficiently compressible that when the weight of the cage i6 is suspended thereon the members 70 and 72 will be suiiciently compressed to raise the articulated rods S2 as shown in Figures 1 and 3 so that the weight of the cage is transmitted through the support members 62 and 64 and the resilient members 7G and 72 to the yokes 58 and thence 3 to the lifting members 36 and 3S then to the cable 30.

The ends of the arms 54 and 56 are provided with articulated brake shoes 74 and 76 each of which comprisesv a flat end 80 on the end of the arm together with a horizontally pivotal metal shoe supporting member 82. in which is, provided a suitable friction element such as a wooden block 84 the whole being held together by means of a suitable rivet 86. When the members 70 and 72 are compressed the shoes 74 and 76 are withdrawn from contact with the wall 12 so that the cage 16 was freely moved upwardly or downwardly in the shaft. In the event that the cable 30 should break or be released the resilient elements 70 and 72 will force down the arm 52 so that the shoes 74 and 76 will be pressed into engaging contact with the wall 12 to effectively prevent the fall of the cage 16. Suitable stops 86 and 8S are provided below the articulation point of the arms 52 so that the articulation point cannot depend past center to release the pressure o-n the shoes.

It will be thus be seen that as long as the weight of thev cage 16 is suspended from the cable 30 the brake shoes 74 and 76 will be withdrawn out of contact with the cable wall but as soon as the brake is released the resilient elements will immediately produce the necessary movement to jarnb the shoes into engagement with the wall of the shaft so that it is unnecessary to wait for the cage to attain the velocity of free fall before the shoes are set.

Thus, not only will the device automatically set immediately upon release of the break from the cable but will operate before the cage is in high motion so that there is no necessity of interrupting the free fall velocity of the cage.

While for purpose of exemplication a preferred embodiment of the invention has been shown and described according to the best present understanding thereof, it will be apparent to those skilled in the art that changes may be in the construction and arrangement of parts thereof without departing from the true spirit and purpose of the invention.

What is claimed as new is as follows:

1. In combination, a hoist for movement in a vertical shaft having vertical guide rails secured on opposite side wall portions, a tioor, a pair of opposite end members extending vertically from said floor, a top extending transversely across opposite side edge portions of said end members in parallel relationship to said oor, a pair of oppositely disposed guide brackets extending laterally from the end members of the hoist for sliding and guided engagement with the vertical guide rails of the vertical shaft, a lift member including a bight portion medially securable to a lift cable, the bight portion of said lift member terminating at opposite ends in depending force transmitting legs extending through the top of the hoist in parallel relation to the end members, a lateral support bracket extending from the opposite end members of the hoist and including a vertical apertured portion reciprocably receiving a force transmitting leg therethrough, said legs each including a lower end portion having a bridle element pivotally supporting a transversely extending articulated brake rod, a compressible coil spring circumposed on each leg of the lift member between the bridle element and the lateral support bracket through which the leg extends, the articulated brake rod including a pair of elongated arms pivotally supported at one end on a horizontal pivot axis in the bridle element, the opposite ends of said arms extending transversely beyond opposite edges of the floor of the hoist, articulated brake shoes supported on a horizontal pivot axis on an end portion of said arms beyond the edge of the floor for engagement with opposite side wall portions of the vertical shaft, and stirrup elements extending upwardly from the floor of said hoist in transverse spaced alignment adjacent the edges of` said iloor, said stirrups including a portion overlying the arms and including a horizontally pivoted roller element supported therein and engageable with a lower intermediate portion of said arms.

2. In the combination as set forth in claim 1 wherein said articulated brake shoes include a metal shoe supporting member having a friction block extending outwardly therefrom, the arms of the articulated brake rod including a vertically disposed attened end portion extending beyond the opposite edges of the oor of the hoist, said flattened end portions of the arms extending into a portion of the brake shoe and friction element, and a horizontally disposed securing element extending through the flattened end portion of the arm, the brake shoe, and the friction element.

References Cited in the file of this patent UNITED STATES PATENTS Re. 21,405 Stiehl Mar. 19, 1940 416,112 Lainesse Nov. 26, 1889 870,411 Boren Nov. 5, 1907 902,371 Bruce Oct. 27, 1908 1,041,019 Carson et al Oct. 15, 1912 1,124,609 Guffey lan. 12, 1915 1,696,557 Tomlinv Dec. 25, 1928 

